1. Field of the Invention
The present invention relates to microfilm cameras and, more particularly the present invention relates to a computer controlled microfilm camera system and method providing the capability of automated format selection and row or column mode operation for microfilming data onto pre-cut individual microfiche film sheets.
2. The Prior Art
Microfilm camera systems have long been used for producing very small film copies of documents or data. When it is developed the exposed roll of microfilm is cut into sheets, called microfiche, which are typically 105 mm by 148 mm (approximate 41/2 inches by 6 inches) in size. In the most common format, 98 separate exposures may be stored on a single microfiche.
In the past, the prior art camera systems used rolls of microfilm that were commonly 100 feet in length. Thus, before developing, each roll contained over 19,000 individual exposures. Although such systems are valuable in applications where large numbers of documents are to be microfilmed over a relatively short period of time, these systems are simply unacceptable for the small volume user who may wish to record only a few documents and to produce only several microfiche in a short time period. The roll system is not economically adaptable for that purpose since it is not possible to produce single microfiche without losing in excess of 6 feet off the roll of microfilm each time that is done. Thus, the user must wait until the entire roll has been exposed in order to eliminate such waste.
In order to meet the need of the small volume user, several microfilm camera systems have been developed for copying documents onto a single, pre-cut sheet of microfilm. In such systems, the microfilm sheet is typically contained in a cartridge that is loaded into the camera prior to exposure of the film. In one instance, the cartridge has a face plate which is removed after the cartridge is in the camera. After exposure of the film, and prior to removing the cartridge from the camera, the face plate is replaced on the cartridge.
Another known type of camera system for small volume users involves use of a cartridge from which the microfilm sheet is completely removed while the cartridge and sheet are in the camera. After exposure the microfilm sheet is placed into a second "holding cartridge" in preparation for processing.
Although these prior art camera systems provide a means by which the small volume user may economically produce individual microfiche, they are not entirely satisfactory for a number of reasons.
One of the foremost problems with such camera systems is that the user is restricted to producing microfiche in only a single format. In other words, even though the user may be filming documents of various sizes, he can only produce microfiche of a particular frame size, with a set number of rows and columns per microfiche. This results in an inefficient use of film for many users. And if a different format is required, it has been necessary to utilize a different camera system, which increases both the expense and inconvenience to the user.
Another difficulty of the single sheet camera systems developed for small users is that they typically record the microfilmed data in only a single mode--i.e., either row by row (row mode), or column by column (column mode). In some applications it is desirable to be able to change the mode of recording data from row mode to column mode or vice versa.
Yet another problem with the present microfiche camera systems concerns the processing of the exposed film. In microfilm camera systems which use rolls of film, the exposed film is collected in a lightproof canister which may be removed from the camera and loaded into one of several types of well-known daylight loading processors which are commercially available. In this type of processing, the film is fed directly from the canister into the processor which then develops the film to produce the finished microfiche.
To date, the microfilm camera systems that have been developed for use with single, pre-cut film sheets have not been usable with daylight loading microfilm processors. For example, in the case where the film cartridge has a removable face, it is impossible to unload the exposed film from the cartridge into such a daylight loading processor. It has also not been possible to load the exposed film from a "holding cartridge" type camera system into a daylight loading processor. In each of these two cases, the exposed film must be processed in a darkroom or similar environment. Thus, the low volume user who desires to produce single microfiche with a fairly quick turnaround must either provide his own darkroom processing facilities, or he must be prepared to spend additional time and money to have the microfilm processed commercially.
What is needed in the art is a microfilm camera system designed for use with pre-cut, single microfiche film sheets and which offers the user a multiplicity of formats from which to choose, as well as permitting the user to specify row or column mode operation. It would be a further important advance in the art to provide a system wherein each film sheet can be retrieved from the camera system after exposure and immediately process in a daylight loading processor, with no darkroom or similar handling required. Such an invention is described and claimed herein.